1. Field of the Invention
This invention relates to a biodegradable osteosynthesis implant constructed of a polymeric biodegradable base material with active ingredients that aid regeneration of bone tissue in a fracture area.
2. Description of Prior Art
Metallic implants have been used in medicine for more than 200 years for fixation of broken bones. Success was achieved in the last decades with the selection of suitable compatible metal alloys to optimize the mechanical load-bearing capacity, and above all the tissue tolerance of these implants so that corrosion and rejection reactions rarely occur. Complications because of the metallic implants can arise in the course of X-ray and tomographic diagnostic processes. One main disadvantage associated with conventional implants is that metallic implants cannot remain in the human body over an unlimited time. It is therefore necessary to perform a second surgical procedure for removing the implant after the fracture has healed. This not only involves another stress for the patient, but also results in considerable costs for the second surgical procedure and the necessary second stay of a patient in a hospital. In addition, direct and indirect costs result from loss of work and after-treatment during the second healing of the wound. Therefore efforts have been made over a considerable period of time to replace the metallic materials with biodegradable polymers so that removal of the implant after healing of the fracture is no longer necessary.
The use of a biodegradable plate in connection with osteosynthesis was first described by D. E. Cutright and E. E. Hunsuck in the Journal of Oral Surgery, Volume 33, pages 28 to 34 (1972).
In developing novel biodegradable implants, it has been a goal to replace metallic implants. Thus the implant had to fix the bone fragments in place and support the mechanical forces acting on the bone.
However, implants made of absorbable polyesters have inferior mechanical load-bearing capabilities when compared to implants made of metal. Although it was possible using suitable production methods, for example injection molding methods, and using optimized material mixtures to produce implants, for example fiber-reinforced implants, which could resist great tensile stresses, the flexible strength of such workpieces is relatively low and far below that of metal implants. A range of applications of biodegradable osteosynthesis materials is limited to lightly stressed, rapidly healing fractures. Such fractures can occur, for example, on the skull, such as a roof of the skull, a cheek bone or an upper jaw.